It is well known that in order to satisfactorily make up a threaded connection between two members having mating threads, such as oil field tubing and casing joints or bolts, that a specified number of threads have to be engaged and a specific torque applied, particularly in the case of tubular goods which are required to be leak proof. Prior U.S. Pat. Nos. 3,368,396; 3,606,664; 3,745,820 illustrate apparatus for measuring torque and counting the number of turns a threaded connection is engaged. However, the prior art devices only indicate that a "bad joint" has been made up when certain predetermined conditions are found to exist. It is desired that failure in a made-up joint be predicted and detected as soon as possible so that additional damage to the threads does not occur and also to avoid the continual application of torque to defective joints because it is very difficult and time-consuming to uncouple defective threaded connections.
Generally, when a threaded connection begins to interengage, more torque is required to rotate one of the members relative to the other member. When the applied torque reaches a predetermined point, it is referred to as reference torque and is the starting point for counting the number of turns of one member relative to the other for measuring engagement of the threads. However, it has been found that during actual makeup of the threaded connection, bending of one of the threaded members relative to the other threaded member, such as occurs on a drilling rig when rotating pipe sways, creates a false indication of reference torque during initial makeup before proper actual thread makeup is started. With the prior art devices, any time torque was exceeded, turn counts were measured with the counts discontinuing when torque fell below reference torque. The false turns were included as a portion of the final turns producing an error that resulted in insufficient actual thread makeup. However, the present invention overcomes the problem of erroneous turn count by utilizing the fact that when the torque drops below reference torque the turns introduced, while the torque, was above reference torque are removed. When torque is maintained above reference torque number of turns are accumulated.